1. Field of the Invention
The present invention generally relates to digital signal recording and reproducing apparatus and, more particularly, to a digital signal recording and reproducing apparatus for use with a digital video tape recorder.
2. Description of the Prior Art
In a digital signal recording and reproducing apparatus according to the prior art, and a video signal is converted into a digital signal, and recorded in and reproduced from a tape by using a rotary head.
In such prior art digital signal recording and reproducing apparatus, the digital signal recorded and reproduced is generally divided into a plurality of digital signals which are supplied to respective signal channels and the digital signals from each channel are recorded and reproduced by respective independent heads. In this case, the plurality of heads which respectively correspond to the plurality of signal channels, are integrally formed as one body or unit so as to be mounted with relative ease on a head drum.
Recording signals are normally recorded at similar positions in each track on the tape to produce a recording format as, for example, shown in FIG. 1, thereby effectively utilizing the tape. As a result, in the head unit having the plurality of heads, a signal supplied to and recorded by a head in a succeeding position along the scanning direction (hereinafter, the succeeding head) is time delayed by an amount, corresponding to a distance between the succeeding head and the head having the preceding position in the scanning direction (hereinafter, the preceding head).
When the above-mentioned digital signal recording and reproducing apparatus is utilized in a video tape recorder (VTR), a video signal data and audio signal data are recorded in separate recording areas. In this case, respective, data signals must be independently recorded as, for example, by recording the audio signal in a so-called after-recording mode.
However, when using the above-described head unit it is at times very difficult to position one head in a recording mode so as to avoid crosstalk effects.
For example, as shown in FIG. 1, when the audio signal is recorded in the after-recording mode, the succeeding head still remains in the recording area of the video signal data when the preceding head reaches the starting portion of the recording area of the audio signal data. If the audio signal is recorded at this time, some amount of recording current is coupled to the succeeding head which, in turn, may negatively influence the video signal data. Therefore, the digital signal recording and PG,4 reproducing apparatus according to the prior art cannot satisfactorily perform the after-recording of respective signals.